*, *::before, *::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html, body {
  width: 100%;
  height: 100%;
  overflow: hidden;
  background: #F5F0E8;
  font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;
  -webkit-font-smoothing: antialiased;
}

#app {
  position: relative;
  width: 100vw;
  height: 100vh;
}

#stage {
  display: block;
  width: 100%;
  height: 100%;
}

/* ---------- overlay ---------- */
#overlay {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(245, 240, 232, 0.97);
  z-index: 10;
  transition: opacity 0.6s ease, visibility 0.6s ease;
}

#overlay.hidden {
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
}

.overlay-inner {
  text-align: center;
  user-select: none;
}

.overlay-inner h1 {
  font-size: 3.2rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: #3C465A;
  margin-bottom: 0.3em;
}

.overlay-inner p {
  font-size: 1.1rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: #8A94A6;
  margin-bottom: 2em;
}

#start-btn {
  font-family: inherit;
  font-size: 1rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: #F5F0E8;
  background: #3C465A;
  border: none;
  padding: 0.7em 2em;
  cursor: pointer;
  transition: background 0.2s;
}

#start-btn:hover, #start-btn:focus {
  background: #5A6B82;
  outline: 2px solid #F2D02B;
}

/* ---------- mute button ---------- */
#mute-btn {
  position: absolute;
  top: 14px;
  right: 14px;
  z-index: 20;
  width: 38px;
  height: 38px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(60, 70, 90, 0.12);
  border-radius: 50%;
  cursor: pointer;
  opacity: 0;
  transition: opacity 0.4s ease;
  font-size: 1.1rem;
}

#mute-btn.visible {
  opacity: 1;
}

#mute-btn:hover {
  background: rgba(60, 70, 90, 0.25);
}

/* ---------- responsive ---------- */
@media (max-width: 600px) {
  .overlay-inner h1 {
    font-size: 2rem;
  }
  .overlay-inner p {
    font-size: 0.85rem;
  }
  #mute-btn {
    top: 8px;
    right: 8px;
    width: 32px;
    height: 32px;
    font-size: 0.95rem;
  }
}